Ignition plug for internal-combustion motors



June 4 1927- 'c, A; RUDQVIST IGNITION PLUG FOR INTERNAL COMBUSTION MOTORS Filed June 26, 1923 2 Sheets-Sheet 1 "14 1927. Jun-e c. A. RUDQVIST IGNITION PLUG FOR INTERNAL CQMBUS'JlI QN MOTORS Filed June 26, 1925 2 Sheets-Sheet 2 Patented June 14, 1927.

UNITED STATES-- GAR-L AUGUST RUIJQVIST, OF STAKET, SWEDEN.

IGNITION PLUG FOR INTERNAL-COMBUSTION MOTORS.

Application filed June 26, 1923,1Seria1 No. 647,931, and. in Sweden June Y, 1923.

This invention relates to improvements in ignition plugs for use in internal. coinbus tion engines and consists in certain means for rendering devices of this kind safe and durable.

One object of the invention is to provide an electrically heated wire ignition plug, in which the difference in length. due to the variation of the temperature to whichthe different elements of the device are subjected, is entirely compensated. 7

Another object of the invention is to pro vide a device of this character, of such construction that the igniter element may be removed from and replaced in the cylinder,

and to this end is enclosed in a housing pro vided with a valve arrangement in order to ensure absolute tightness for the pressure gases in the cylinder, when the igniter element is removed from the combustion chamher.

A further object of the invention is to provide a safe and reliable insulation for the wire igniter element in order to prevent short circuiting.

A further object of my invention is to provide an auxiliary igniting body with the object of keeping up the ignitions at times when the motor is running at reduced load or when the load is thrown off, and with the further object of reducing the lapse of time during which the wire igniter element needs to be in operation on starting the motor.

A still further object of my invention is to provide a construction wherein the igniting device may be indirectly cooled by means of a water jacket in the housing, said jacket at the same time reducing the temperature of the wall of the combustion chamber.

My invention is illustrated in the accompanying drawings as follows:

Figure 1 is a side elevation of one form of ignition-plug embodying the features of the present invention, with the igniter ele ment in its inoperative position.

.Figure 2 is a vertical central section of said plug with the igniter element inits operative position.

Figure 3 is a vertical central section, on a smaller scale, of the combustion chamber of an internal combustionengine fittedwith an ignition-plug constructed according to Figure 1.

Figure 4 isa Vertical central section of a modified form of theignition-plug.

Figure 5 is a side elevation of said modified form of the vignition-plug.

Figure 6 is a vertical central section, on a smaller scale, of the combustion chamber of an internal combustion motor fitted with an ignition-plug according to Figure 41:.

The body or block 1, surrounding the hollow valve sleeve 2, is provided with threaded projections 3 and 4t. Said projections are provided with bore holes communicating with a hollow chamber or jacket 5 between the block 1 and the sleeve 2. Through jacket 5 a cooling medium, water or the like, may be led, the bore holes of the projections 3 and 4: serving as inlet and outlet respectively. At the lower end of sleeve 2 there is a threaded part 6 for attaching the ignition-plug to the motor, and also a conical part 7 serving as tightening means at the lower part of jacket 5. The upper part of said jacket is made water tigl'it by means of a packing 8 between tightening surfaces on the block and the sleeve. For tightening the ignition-plug against the motor the block 1 is provided with an off-set part 9.

At the upper end of sleeve 2 there is a hexagonal part 10 and two slits 11, 11, each extending axially from the top edge through the wall of the sleeve and terminating in a peripheral recess, as shown in Figure 1. The slits are arranged diametrically or nearly diametrically opposite each other- The upper edge of sleeve 2 has two wedgeshaped surfaces 12, 13, also diametrically opposite each other, or approximately so, said surfaces terminating in upwardly extending stops or projections 1 1, 15 respectively. In the slits 11, 11, looking springs 16, 16 are adapted to operate, said locking sprmgs being rigidly connected to an axially movable valve bushing 17 disposedin the hollow of sleeve 2.

in the position of bushing 17 shown in Fig. 1 the bent elastic parts 18, 18 of springs 16, 16, are resting against the cam surfaces at 12, 13 at the upper end of sleeve 2 If the bushing 17 is noted through a certain angle the elastic parts 18, 18 will be set so as to force bushing 17 upward. Secured in the lower end of bushing 17 by means of threads 20 is a housing 19 which encloses the igniter 6l6111611t23. lhe housing is provided with an outwardly facing valve face 21. VVhen the bushing 17 is forced upward by means of the springs 18, 18 mentioned above, said lDU ' position shown in Fig. 2, the element having seat 22of the valve sleeve2.

' any valve face 21 will contact with a valve seat at the loweredge of sleeve 2, thus forming a tight joint and protecting the igniter element when the motor is running.

Owing to the elastic connection between parts 2, 16 and 17 the'tightening action of valve face 21 will not become influenced by the changes of length of parts 2 and 17, due to the changes of temperature. The pitch of the wed e-shaped surfaces 12, 13 willset the springs 18, 18 atrifie more than is necessary to compensate for thelength variations.

Between the valve face 21 and an upper *alve face corresponding toa valve seat 22 of stud 2, the valve bushing 17 is guided in the body of the ignition plug by means of its cylindrical, closely fitting ;,engagement with the'sleeve2r 7 In the position shown in Fig. 1 the igniter element is in inoperative position. In the been shifted to operative position, a conical shoulder-or valve face on bushing 17 is forced into contact with the conical valve In this positi n, the locking springs 16, 16 are turned into the lower recesses of slits 11, 11, thus locking the bushing in its lowermost position in the sleeve 2. The upper parts of the locking springs bein tion will becomerigid.

The housing 19 is provided ,with side openings to admit the fuel to the igniter element enclosed therein. The igniter element consists o f-a spirally wound wire 23 and a rod 24, the lower end 25 of the rod being electrically connected to the wire. By means of a. contact pin 27,-the rod may be connected g stiff, this locking acto aconduit wire 26, said conduit wire being attached to a contact piece28, provided with a button 29, made ofnonconducting material.

The pin 27 is continued by a rod 30, thread ed intoan insulating nipple 31. At, the lower end, the rod 30 by means of screw threads is connected to the upper end of rod 24. A

guide-bushing 32 for guiding rod 2 1 is rigidly fixed in bushing 17 between a tubular member 31 and the housing 19, said tubular member being screwed into the upper part of the valve bushing 17. A nipple 32 threaded into the guide bushing 32 surrounds an insulating bushing 34 for the upper part of rod 24 The upper part 35 of valve bushing 17 is provided with handles 36, diametrically oppositely disposed as shown by dot and dash lines in Figure 1 i The rod 24 is surrounded by a tubular insulating element 2% of quartz, glimmer or other non-conducting material, arranged between the spirals of the wire and therodi The object of; this insulating element is to prevent the rod from coming into electrical contact with the spiral windings of the wire element 23, such a connection being liable to cause short-circuiting between the rod and the spirals. Thus the electric current will pass through the whole spiral, causing the entire length to glow. Through the upper part 35 of the bushing 17 extend screws 37 connected to the inner parts of the locking springs 16 so as to rigidly lira said locking springs to .thebushing 17. The upper part of the spiral igniter wire element 23 is fixed in the guide bushing 32, whereby electric connection with the body of ,the motor is established.

The locking elements may be provided device will remain heated to such a degree that the ignition of thefuel will take place at the right moment. This device consists of a ball-shaped body or bulb 38, connected' with housing 19 by means of a neck 39, as shown in Fig. 2. While the body and neck are shown herein as integral with the housing 19, it is obvious that they may be made separate therefrom and electrically connected thereto. Owing to the comparatively small dimensions of this body or bulb, the heat of the decreased combustion will be sufiicient to keep up the temperature of the body to the required degree.

In the form shown in Figures i and 5 the igniting spiral a and the rod 7) are rigidly attached to the body or block 0, said body being provided with a threaded part (I for attaching the ignition plug to the combustion chamber 0. In this modified form the igniter element is not movably arrange-d.

In order to protect the spiral wire element a from the heat of the combustion, when the motor is running, the body 0 is titted with a cooling wall f surrounded by a water jacket 9 with pipe connections h and h -for the cooling water. This cooling arrangement may be regulated in such a manner that the wire element a will-not become injured by the increased heat arising from the successive combustion in the cylinder. By means of the cooling action, it will be possible to" maintain alower degree of heat in the space between the wire a and the'wall f, and the dimensions of said space may be chosen to suit the requirements.

Between the rod 6 and the spiral a an insulating bushing is inserted in order to prevent short-circuiting. At the upper end the rod 7; is formed into a contact pin 1) for the contact socket is in the contact knob 7', said contact socket being connected to an ion electric conduit wire 70. The rod 5 is provided with a flange 5 which may be forced up against the upper surface of a bushing Z closing up against a tightening tace Z. To the lower end of said bushing, the wire element a is attached. The flange 6 is forced up against the bushing Z by means of: a nipple m, screwed into a threaded socket n at the top of the body 0. By unscrewing the nipple m, the igniter element a, Z) and bushing Z may be taken out from the body 0 independently of the cooling jacket l3etween the flange b and the adjoining faces of the nipple m and the bushing Z washers of insulating material are inserted. The cooling wall f forms the cylindrical part of a bushing, at the upper end fitted with threads f and screwed into the'threaded socket n to form a water tight joint at the face f At the lower end the bushing is provided with a valve face 7", closing up against a corresponding seat at the lower end of the body 0, the cooling water jacket being arranged between the valve arrangement f and the joint 7". The conduits 7L and k serving as inlet and outlet for the cooling water, are arranged in nipples and h attached to the body 0 by means of screws g. These screws are made hollow from one end, as shown in Figure 4t, and the hollow spaces of the screws are connected to the conduits h and if respectively, as well as to the jacket space 9. A tight connection between the conduit pieces is achieved by means of joints 9".

The ignition plug described above may be used for all kinds of internal combustion motors of the semi-Diesel type or for other types requiring a specially heated ignite]: for starting or running.

It is obvious that changes in the term of construction and arrangements of parts of this device may be resorted to within the scope of the invention.

Having thus fully disclosed my invention, what I claim as new and desire to secure by Letters Patent is,

1. An ignition plug, comprising,in combination, a sleeve adapted to be secured in the cylinder wall of an internal combustion engine, a bushing axially movable in said sleeve and carrying an igniter element adapted to be retracted into and. protracted from said sleeve, and a. pair of resilient members carried by the bushing and adapted to engage said sleeve thereby to yieldably lock said bushing in its retracted position.

2. An ignition plug, comprising, in combination, a sleeve adapted to be secured in the cylinder wall of an internal combustion engine, said sleeve having a pair of diametrically opposite bayonet slots and provided at its upper edge with a pair of diametrically opposite cam portions, a bushing axially movable in said sleeve and carrying an ign'iter element adapted to be retracted into and protracted from said sleeve, and a pair of members carried by the bushing and. each provided with a rigid portion and a resilient portion adapted to engage said bayonet slots and said cam portions respectively for locking the bushing in its protracted and retracted positions.

8. An ignition plug, comprising, in combination, a sleeve adapted to be secured in the cylinder wall of an internal combustion engine, a bushing axially movable in said sleeve and carrying an igniter element adapted to be retracted into and protracted from said sleeve, said bushing and sleeve having cooperating contact faces adapted to limit the protracting and retractii'ig movement of the bushing, locking means for rigidly retaining the bushing in its pro tracted position and yieldably retaining it in its retracted position, and an auxiliary igniter body carried by said bushing and adapted to be exposed in the cylinder when the first igniter element is retracted into the sleeve. r

In testimony whereof I have signed my name to this specification.

CARL AUGUST RUDQVIST. 

